1. Field of the Invention
This invention relates to shafts and mechanisms for connecting implement shafts to power takeoff shafts on vehicles especially tractors.
A problem exists in such connection. When the implement shaft and connecting yoke are fully protected from accidental contact by shielding, it is difficult to turn the implement shaft to align internal splines in the shaft with external splines on the vehicle power takeoff stub shaft.
This invention provides a means of locking a protective shielding to an implement power takeoff shaft that permits the shaft to be turned while locking the shaft and which rotates freely on the shaft after the shaft is attached to the stub shaft of a vehicle.
2. Description of the Prior Art
Revelant prior patents existing in the United States Patent and Trademark Office include: U.S. Pat. Nos. 3,969,033, 3,551,013, 3,884,536, 3,344,618.
U.S. Pat. No. 3,969,033 shows a torque transmitting coupling that has a free spinning shield disposed around the housing. The guard is attached to the coupling by means of two snap rings.
U.S. Pat. No. 3,551,013 shows a power shaft coupling device surrounded by a safety shield. A collar engageable with splines on the exterior of the power takeoff (PTO) shaft allows for quick aligning of the two shafts.
U.S. Pat. No. 3,884,536 shows a protective guard device for a transmission shaft with conical guard members extending over the yoke arms.
U.S. Pat. No. 3,344,618 shows a safety shield that can be used in PTO and implement couplings. The shield can rotate independently of the shaft and coupling.
Other less pertinent patents that represent a cross section of PTO shaft shields include: U.S. Pat. Nos. 4,008,583, 3,992,120, 3,960,850, 2,953,000.
The primary object of the present invention is to provide a power takeoff shaft coupling apparatus comprising a sleeve having internal splines for receiving external splines of a power takeoff stub shaft, the sleeve having a radial opening therein, detent means positioned in the radial opening for moving radially inward through the opening to engage a groove in a power takeoff stub shaft, detent locking means mounted on the sleeve adjacent the detent means and slidable on the sleeve from a position radially aligned with the detent means for locking the detent means to an inward position longitudinally displaced from the detent means for releasing the detent means to a radially outward position, an outer collar rotatably and slidably mounted on the sleeve, the outer collar having abutment means oposed to the detent means for pushing the detent means to its second, disengaged position, an inner collar mounted on the sleeve within the outer collar and secured to the sleeve, the inner collar and the outer collar having complementary teeth for permitting relative turning of the collars in a first direction and for preventing relative turning of the collars in a second opposite direction, whereby when the complementary teeth are operatively engaged, the outer collar turns the sleeve via the inner collar in a first direction to align internal splines in the sleeve with external splines on a power takeoff stub shaft.
A further object of the present invention is to provide a power takeoff shaft coupling apparatus further comprising a detent holdout means slidably mounted within the sleeve between a first active position radially aligned with the radial opening and the detent and a second longitudinally displaced inoperative position for releasing the detent means to move radially inward.
Still another object of the present invention is to provide a power takeoff shaft coupling apparatus wherein said sleeve has a first opening for receiving a power takeoff stub shaft and further comprising an abutment mounted at a second longitudinal end of the sleeve, and a first compression spring positioned between the abutment and the detent disabling means for urging the detent disabling means into an operative position, whereby, when a stub shaft is inserted in the sleeve, the stub shaft pushes the detent disabling means towards the abutment and permits the detent to move radially inward into a groove in the stub shaft.
Another object of the present invention is to provide a power takeoff shaft coupling apparatus wherein said sleeve comprises a radial extension longitudinally remove from the inner collar and further comprising a relatively heavy spring positioned on the sleeve between the radial extension and the detent locking means for urging the locking means from its second inoperative position to its first operative position radially aligned with the detent means.
A further object of the present invention is to provide a power takeoff shaft coupling apparatus wherein the said detent locking means comprises an inner surface displaced outward and upward in the direction of the detent means whereby the detent means and the inner surface cooperate to move the detent means radially inward in response to movement of the detent locking means to its second radially aligned operative position.
Another object of the present invention is to provide a power takeoff shaft coupling apparatus wherein the said apparatus further comprises a relatively light compression spring mounted between the detent locking means and the abutment means on the outer collar for urging the abutment means away from the detent locking means towards engagement with the inner collar.
An additional object of the present invention is to provide a power takeoff shaft coupling apparatus wherein the outer sleeve surrounds the inner sleeve, the detent means, the detent locking means and a portion of the sleeve, whereby the inner sleeve, the detent means and the detent locking means are protected from accidental contact.
Still another object of the present invention is to provide a power takeoff shaft coupling apparatus wherein the sleeve further comprises a yoke on an end thereof opposite an open end which receives a power takeoff stub shaft and further comprises a bell mounted on the sleeve for relative rotation, whereby the yoke and the sleeve may rotate within the bell, the bell having an inner end extending within the outer collar whereby the outer collar and bell cooperate to prevent accidental contact with the sleeve.
Objects of the invention are apparent in the above and ongoing description and claims and the drawings.